Had the same thing happen to me last spring with a logo job for a restaurant. Guy paid the deposit, I sent proofs, he went quiet for three weeks, then came back asking for the final files without paying the rest. I held them until he paid but it was two months of chasing him. Switched to the thirds thing after that and honestly it's not as much of a hassle as it sounds. You just bill at three clear points and the client never feels like they're handing over a huge chunk at once. Takes one extra invoice and a short email each time. Worth it if you ask me, because the guy who ghosts after paying half will still ghost on thirds but at least you're only out 25% instead of the whole balance.